Excess of Neurons in the Human Newborn Mediodorsal Thalamus Compared with That of the Adult

Abstract

The aim of this study was to quantify the total number of neurons and glial cells in the mediodorsal nucleus of the thalamus (MD) of 8 newborn human brains, in comparison to 8 adult human brains. The estimates of the cell numbers were obtained using the stereological principles of the optical fractionator. In the case of the adults, the total number of neurons in the entire MD was an average of 41% lower than in the newborn, which was statistically highly significant (P < 0.001). The estimated average total number of neurons in MD thalamus of the newborns was 11.2 million (coefficient of variation [CV] = standard deviation/mean = 0.16), compared with the adults' 6.43 million (CV = 0.15). The glial cell numbers were substantially higher in the adult brains, with an increase of almost 4 times from 10.6 million at birth to 36.3 million in the fully developed adult brain. This is the first demonstration of a higher number of human neurons in the brain of newborns compared with the adult.

Neuron and Glial Cell Numbers in the Mediodorsal Thalamic Nucleus in Brains of Schizophrenic Subjects

“…Within our inhomogeneous sample, some schizophrenic patients thus exhibited relative high neuron numbers in MD, while others exhibited relative low neuron numbers. A prior study from our laboratory showed an excess of neurons in the MD of normal newborn brains with a total neuron number of 11.2 x 10 6 at birth, compared to 6.43 x 10 6 in the adult brain (Abitz et al, 2007). The selection process by which some neurons survive and other neurons undergo apoptosis during development may thus be interrupted in some yet unknown way in the MD of schizophrenic subjects.…”

A common neonatal image phenotype predicts adverse neurodevelopmental outcome in children born preterm

“…The fit line with 95% confidence interval for the population is displayed. (14) 110 (17) 116 (11) The nucleus has a unique developmentally regulated pattern of neuronal death and survival in that there is a relative excess in neuronal number in the human newborn compared with the adult (Abitz et al, 2007). This could be explained by a second wave of neuronal migration from the telencephalic ganglionic eminence to the dorsal thalamus after the earlier migration of neurones from the ventricular zone (Letinic and Rakic, 2001;Bystron et al, 2008).…”

Robust subdivision of the thalamus in children based on probability distribution functions calculated from probabilistic tractography

“…Furthermore, as proof of concept, they demonstrated that in a premature-born child with a porencephalic cyst and with extensive white matter injury, the pattern and volume of thalamo-cortical connections were severely compromised. At two years of age, however there is still significant ongoing development in the brain (Abitz et al, 2007) and a full evaluation of neurological and cognitive functions is often difficult. Published studies demonstrating thalamic parcellation have therefore been conducted only in adults and very young children and so far very limited data about the sub-structures of the thalamus exist in children.…”